1. Field Of The Invention
The invention relates generally to billing in telecommunications networks, and in particular to a system and method for improving efficiency in billing for mobile telecommunications services.
2. Background Information
A multitude of mobile communications systems have been established throughout the world. These systems include older systems, such as, for example, Nordic Mobile Telephone (NMT), Advanced Mobile Phone System (AMPS), Total Access Communications System (TACS) as well as newer digital systems, for example, Global System for Mobile communications (GSM) and Personal Communications System (PCS). While these systems differ in many details, they are similar in many respects. In particular, all mobile systems have similar problems associated with inter-system billing. In order to simplify the description of the present invention, the present invention is described in the context of the GSM. However, the GSM is used merely as an example of a mobile communications system. The principles of the present invention are not limited to GSM; they are equally applicable to other mobile telecommunications systems as well.
In 1982, the global system for mobile communications (GSM) was established in Europe, to provide a cellular mobile radio system. The primary function of the GSM is to provide a full roaming mobile telephone service. The GSM protocol has been selected for use around the world for digital mobile telephone service. The principles of operation of the existing GSM digital mobile telephone system is described in the following references:
Balston, D. M., "Pan-European Cellular Radio", IEEE Electrical and Communications Journal, No. 1, pp. 7-13, 1989.
Goodman, D. J., "Second Generation Wireless Information Networks", IEEE Transactions on Vehicular Technology, VT-40, May 1991, pp. 366-374.
Pautet, M. B., and Mouly, M., "GSM Protocol Architecture: Radio Subsystem Signaling", IEEE Vehicular Technology Conference, May 1991, pp. 326-332.
A problem arises when calls involving roaming mobile subscribers must be billed. Whenever a call involving a roaming subscriber is completed, billing records for that call must be sent to the subscriber's home system in order for the subscriber to be billed. Although the GSM specifications specify the information which must be included in a billing record, they do not specify a particular format which must be used. Consequently, in Europe, a situation has arisen in which each GSM system uses a different format for its billing records. Each billing record received must be reformatted to the format used by the system receiving the record. Because there are a plurality of systems, each with its own format, each system must be capable of reformatting messages received in a plurality of formats. This places an overhead burden on each system's billing processing systems.
The billing records are used not only to generate subscriber bills, but to facilitate reconciliation between telecommunications carriers. Each call originated within a particular carrier's mobile system entitles the carrier to receive at least a portion of the amount which is billed to the subscriber. Periodically, all carriers must reconcile the amounts they are due from other carriers and the amount payable to other carriers. If the amounts due from and payable to another carrier are not equal, one carrier must pay the other the difference. Billing records are used to generate reconciliation information. Multiple formats for billing records causes an overhead burden on this process also.
This problem may be even worse in the United States, in which there are even more independent PCS systems. Many PCS systems have adopted the GSM standard. If each PCS system adopted a different format for its billing records, as is the case in Europe, the overhead burden would be even greater. This problem is shown by the example of a call placed from a mobile station located in one mobile network to a mobile station located in another mobile network. Typically, such a call would be handled by an originating mobile network, a local land-line network, a long distance network, a remote land-line network and a destination mobile network. Five telecommunications networks are involved. The call causes each network to generate traffic information about the call. Each network must then process their respective traffic information and separately generate billing information for its portion of the call. Much of this information must be communicated to some other network in order for proper billing and reconciliation to be completed. Each network which sends billing information may send the information in a different format. Each network which receives billing information must reformat the received information in order to process the information. With a large number of possible formats, the overhead burden of reformatting each record may become excessive. A need exists to reduce the amount of reformatting of call detail records which must be performed for wireless calls.